Packing for air-brake cylinders and the like



June 4, 1929. G. cHRlsTENsoN 1,715,406

PACKING FOR AIR BRAKE CYLINDERS AND THE LIKE Filed July 50, 1926 @Wwww?,

. ifys Patented June 4, 1929.

Niven GEORGE CHRISTENSON, OF NORTH PLAINFIELD, NEW JERSEY, ASSIGNOR, BYMESNE ASSIGNMENTS, T J OHNS-MANVILLE CORPORATION, OF NEW Y0, N. Y., AOOR- POBATION 0F NEW YORK.

PACKING FOR AIR-BRAKE CYLINDEBS AND THE LIKE.

Application led .uly 30,

'My' invention relates to piston packings, and particularly packings forair brake cylinders which, with respect to the actuating iiuid underpressure are single-acting. The

principal objects to which my inventionis directed are: elimination ofleakage, simplication of structure, ease.of replacement and repair.Subsidiary objects and advantages will appear from the followingdescription. In the drawings hereto annexed, which depict a structureexemplifying'my invention, as applied to an air brake cylinder,

Figure 1 shows, in axial mid-section, portions of an air brake cylinder,with its pisl5 ton, piston rod, and release-spring, and

Figure 2 shows, in mid-section, a modified form of packing cup, and itsrelationship to other parts of the brake-apparatus.

Referring to the drawings, C, (Fi 1) l represents the cylinder in whichthe rake actuating piston H, with its rod P, works to a ply the brakeswhen air under pressure is a mitted at the intake B.` B constitutes thehead of cylinder C. R represents the usual release-spring, which acts toreturn the 'piston H to its brake-release position when the air pressureis released.

I eliminate the follower plate and its holding studs, which heretoforehave been associated with and carried by the air brake piston, and also,instead of the annular packing'ring which hasbeen used, confined betweenthe iston and followerlate, and j through which, by the necessities oconstruction, the holding studs yfor the follower plate have passed, Iemploy a packing cup such as A, which is an imperforate disc of suitableacking material, and merely rests on the plston H, without anymechanical fastening members. This packing cup A is preferably providedwith an upturned cylindrical packing lip A havingthe characteristics ofthe lip shown and described in my United States Letters Patent No.1,273,736, dated July 23, 1918; and the material of which I prefer toform the said packing cup A is that described in the said patent.

In order to permit theA pressure retaining peripheral lip lA from eingcrushed or crippled by coming into contact with the cyllnderl head-B,the packing cup A has an upwardly projecting boss A2 molded on it,y of lsuch proportions that it serves as a stop to upward movement of thepiston H when the a192e. serial ne. 125,927.

used, the guard-boss A2 is provided with a recess A8 which, registeringwith the air intake aperture B provides ample area on which the airpressure may act to impart initial brake-setting movement to the pistonH. This packing cup A (Figs. 1 and 2) is provided also with a centralrecess A4, approximately cylindrical in shape, which, in relation to thepiston boss H provides not only clearance allowing the packing cup tomake surface contact with the piston outt,

side the said boss -H but also a space with walls adapted to afford ahold for a hook or other tool when it becomes necessary to remove thecup A from the cylinder C. l.

In Fig. 2 the packing cup A is shown as provided with a. number ofguard-studs A5, perferably molded integrally with the cup, arranged in acircle .with spaces'betweenl adjacent studs. These are of such heightthat they perform the lip-protecting function in a manner which makesthem e uivalent to the guard-bossA, shown in Figs. 1 and 2.

It will now be obvious that`the packing cup above described, whenassembled with the members associated with it, presents a continuous'imperforate barrier against all leakage, 4the lip A', in contact withthe cylinder wall providing a practically eilective closure againstleakage of pressure by the lip of the packing.

\ I claim:

1. The combination with a iston, cylinder, cylinder head provided with acentral intake for Huid under pressure, a releasespring to return theiston to head-end po sition, of a piston-pac ing cup consisting ofAspring-pres`sure while clearance remains between the cylinder head andtlie said peripheral 11p, sald guard-boss recessed to provide areatherein for the exertion of pressure by fluid entering through theintake.

2. The lcombination with a piston, cylinder, cylinder head provided witha central intake for fluid under pressure, a releasespring to return thesition, of a piston-pac ing cup consisting of an imperforate disc offlexible material having a peripheral 'upstanding lip for packingcontact with the cylinder wall, and a central projecting guard-boss,adapted `to contact with the cyhnder head. and arrest movement of theiston in response to spring-pressure while c earance remains between thecylinder head and the said peripheral lip, said uard-boss recessed toprovide area therein or the exertion of pressure by fluid enterston tohead-end po.-

ing through the intake, said disc being also provided with a centralrecess adapted to provide air space between said disc and the piston.

3. A unitary packing cup for attachment lo the head of a piston,comprising an imperforatedisk of flexible, somewhat yieldable material,an integrally moulded upstanding peripheral lip upon said-disk, and aninterally moulded'guard projecting upward] rom the central portion `ofthe disk, sai

guard having a greater height than said lip and being similarly formedof yieldable material whereby it may form a cushion between the pistonand cylinder head at the end of the piston stroke and may protect thelip against engagement with the cylinder` head.

Signed by me at New York, New York, this twenty-fourth day of July,1926.

GEORGE oHRis'rENsoN.

